speeds determined by height and spacing; speeds between humps have been observed to be
reduced between 20 and 25 percent on average

based on a limited sample of sites, typical crossing speeds (85th percentile) of 19 mph
have been measured for 3½ inch high, 12 foot humps and of 21 mph for 3 inch high, 14 foot
humps; speeds have been observed to rise to 27 mph within 200 feet downstream

speeds typically increase approximately 0.5 mph midway between humps for each 100 feet
of separation

studies indicate that traffic volumes have been reduced on average by 18 percent
depending on alternative routes available

studies indicate that collisions have been reduced on average by 13 percent on treated
streets (not adjusted for traffic diversion)

most communities limit height to 3-3½ inches, partly because of harsh ride over 4-inch
high humps

possible increase in traffic noise from braking and acceleration of vehicles,
particularly buses and trucks

Emergency Response Issues:

Concern over jarring of emergency rescue vehicles

Approximate delay of between 3 and 5 seconds per hump for fire trucks and up to
10 seconds for ambulance with patient

Typical Cost:

Approximately $2,000 (1997 dollars)

For additional detail, refer to ITEs Recommended Practice entitled Guidelines
for the Design and Application of Speed Humps. Visit the ITE Bookstore for more information about this
publication.